Method, system, and article of manufacture for self-servowriting a disk

ABSTRACT

A compound actuator self-servo writes a hard disk. The compound actuator moves to track n+1. A first head on the compound actuator track follows on track n. The other heads servo write on track n+2. One of the other heads track follow on track n. The first head servo writes track n+2. The value of n is incremented by one, and the process repeats until the entire hard disk is servo written.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method, system, and article ofmanufacture for self-servowriting a disk.

[0003] 2. Description of the Related Art

[0004] Disk drive units with stacked, platter-shaped rigid magneticdisks are used for data storage. The platter-shaped disks rotate about adrive axis. A disk drive unit uses actuators to position a plurality oftransducer heads, such as drive heads, that move radially to the driveaxis to write data to the surfaces of the disks and read data from thesurfaces of the disks. Disks store data in concentric tracks and, in thecurrent art, the density of the tracks may exceed 100,000 tracks perinch.

[0005] To read and write data, a magnetic head must remain accuratelycentered on a selected track. At high track densities, the head may haveto stay centered on the narrow tracks to within a tolerance better thana millionth of an inch. To achieve this level of precision, the headreads position information from tracks permanently written onto a disksurface. The position information is written in special codes calledservo codes. A linear feedback system continually uses the positioninformation (servo codes) to adjust the head to correct for positionerrors.

[0006] In prior art, during manufacture of the disk, a servowriter unitwrites the servo codes on a disk, and the position information remainson the disk for the life of the disk. The servowriter is a specializeddevice used in the manufacture of the disk that includes a large base tominimize the effects of vibration, precision fixtures to hold the targetdisk drive, and a precision laser interferometer based actuator armpositioning mechanism to precisely position the arms radially withrespect to the axis of rotation of the disks in the drive. With highservo track densities, the mechanical vibrations of the disk relative tothe external sensors can affect the accuracy of the servo writersystems. In addition, a clean room environment is required by servowriter systems. Furthermore, servo writer systems are difficult to useto write servo codes on small disk drives.

[0007] Instead of using a servo writing system, self-servo writingtechniques may be used. In self-servo writing, the disk head writesservo patterns as well as reads servo patterns. The servo codes have tobe written with a high degree of accuracy in self-servo writing inhigh-density disk drivers.

[0008]FIG. 1 illustrates a schematic diagram of servo tracks on a diskduring self-servo writing in a manner known in the prior art. In priorart, a head 20 can read and write servo bursts A, B, C, D (referencenumerals 22, 24, 26, 28 respectively) on the disk. The servo bursts maybe any pattern, whose signal amplitude can be read by the head 20. Theservo bursts are of the same width as the width of a data track. Thecenterlines of the servo bursts form servo tracks on a disk. Since, eachservo burst pattern is offset a half servo track width from the previousservo burst pattern, there are twice as many servo tracks as data trackson a disk. To write the servo bursts, the head 20 would first writeservo burst A 22. After writing servo burst A 22, the head 20 moves to aposition where the head reads half of the servo burst A 22, and nothing(i.e., the blank disk). The data read by the head 20 is expressed as acombination of the amplitude of half of servo burst A 30 (obtained byreading half of the servo burst A 22) and white noise 32 (obtained byreading nothing). The head writes the servo burst B 24. However, becauseof the white noise 32 the positioning of the head 20 may not be exactlyat the half servo track offset from servo burst A 22 while writing servoburst B 24. Head 20 writes servo burst C 26 after moving to a positionwhere the head 20 reads half of servo burst B 24, and nothing.Subsequently, head 20 writes servo burst D 28 after moving to a positionwhere the head 20 reads half of servo burst C and nothing.

[0009] The head 20 can self-servo write an entire disk surface. The head20 starts adjacent to a crash stop on the disk surface (the crash stopis a fixed position on the disk at or around the center of the diskadjacent to which is the first servo track). The head 20 writes a servoburst on the first servo track. The head 20 then moves to a positionwhere the head 20 reads half of the first servo track and nothing. Thehead 20 then writes a servo burst on the second servo track. In such amanner the head 20 writes servo tracks from servo track one throughservo track n. At servo track n the head 20 moves to a new positionwhere the head 20 reads an amplitude equal to half of the servo burstfor servo track n and nothing. The head 20 writes the servo burst forservo track n+1 at the new position. In such a manner the head 20 writesservo bursts on servo tracks till the periphery of the disk. However,the servo patterns have positional errors on the disk because whitenoise 32 prevents the head 20 from being positioned at a half servotrack width offset from the previous servo burst pattern.

[0010]FIG. 2 illustrates a prior art self-servo technique used whenservo tracks are written to a disk with multiple surfaces or multipledisks. A first head 48 a track follows, i.e. the first head 48 a readsservo burst A 49 from a first surface 50 a and positions the first head48 a such that a second head 48 b, and a third head 48 c can write todisk surfaces on the basis of the position of the first head 48 a.

[0011] The second head 48 b and a third head 48 c write servo bursts B51, 52 to second surface 48 b and third surface 48 c respectively, onthe basis of the positioning of the first head 48 a FIG. 2 shows thattrack following at 50% of the amplitude of the servo burst A 49 by thefirst head 48 a is imprecise because of the presence of white noise(white noise is the signal read from the blank region of a disksurface). If no white noise or error introducing factors are present,then when the first head 48 a reads 50% of the amplitude of servo burstA 49, the first head 48 a would be half way across the servo burst A 49.Since on physical disk surfaces the head 48 a reads white noise inaddition to the amplitude of servo burst A 49, the first head 48 acannot be positioned exactly half way across the servo burst A 49. Inparticular, when a disk has a very high number of tracks per inch (forexample, over 100,000 tracks per inch), track following is extremelydifficult because the actuator movements cannot position the head 48 ato the precision necessary for track following at 50%.

[0012]FIG. 3 illustrates a prior art technique for positioning the headmore precisely than the prior art techniques shown in FIGS. 1 and 2. Thefigure shows a head 64 and the centerlines of servo track n−1 65 a,servo track n 65 b, and servo track n+1 65 c. FIG. 3 also shows a servoburst A 66 centered on servo track (n−1) 65 a, and a servo burst C 68centered on servo track n+1 65 c. The head 64 moves to a new trackposition over the servo burst A 66, where the head 64 reads half ofservo burst A 70 and white noise 72. At the new position, the head 64also reads half of servo burst C 74 and white noise 76. By subtractingthe half of servo burst C 74 and the white noise 76 from the half ofservo burst A 70 and the white noise 72, the head 64 eliminates theeffect of the white noise 72 and 76, and the head 64 determines theposition that is at a half servo track width offset from servo burst Amore precisely when compared to FIGS. 1 and 2. In FIG. 3, the head 64track follows more precisely when compared to situations where theeffect of white noise is not eliminated. With FIG. 3, because servobursts on servo track n−1 65 a and servo track n+1 65 c are known, thehead 64 can be positioned with greater precision on servo track n 65 bby the noise elimination technique outlined above. As a result highertrack densities can be supported in a disk. Such a noise eliminationtechnique is known in prior art.

[0013] The prior art self-servo writing techniques uses the read sensorsto read servo information from the previously written tracks. The sensoris positioned on the half track boundary and by design the sensor readshalf servo signal information and half no signal information, where theno signal information equates to typically white noise. Reading thiswhite noise introduces a random positioning error into the positioningsystem. Increasing the tracks per inch may introduce an even greaterextent of random unwanted vibration, system electrical noise, diskelectrical noise, and read sensor noise, which results in degradation ofthe servo written information. Servo written information that is notwritten on the concentric track center exposes the servo track followingsystem in the disk drive to errors and compromises data integrity.Although, the noise cancellation technique described in FIG. 3 is knownin prior art, such prior art noise cancellation techniques havedisadvantages. For good noise cancellation precise back and forthindependent movements of heads may be necessary, and such movements havenot been achieved in prior art noise cancellation techniques. These aresome of the disadvantages with the prior art solutions. Hence, there isa need in the art to provide for a method, system, and article ofmanufacture that improves the quality of the servo written tracks.

SUMMARY OF THE PREFERRED EMBODIMENTS

[0014] Provided are a method, system, and article of manufacture forservo writing. An actuator having a first head coupled to a first disksurface and a second head coupled to a second disk surface is moved, andthe first head is positioned on a first track of the first disk surface.The second head writes servo information on a second track of the seconddisk surface. The second head positions on a first track of the seconddisk surface. Servo information is written on a second track of thefirst disk surface, wherein the first and second tracks are any trackson the first and second disk surfaces.

[0015] In another implementation, provided are a method, system, andarticle of manufacture for writing a plurality of tracks in a self-servowriting system. A compound actuator having a first and a second headmoves to an initial track and positions the first head on a previoustrack of a first disk surface. The second head writes a next track of asecond disk surface. The second head positions on the previous track ofthe second disk surface. The first head writes the next track on thefirst disk surface.

[0016] In further implementations, positioning the second head on theprevious track of the second disk surface further comprises moving thesecond head to a position on the second disk surface wherein a whitenoise is eliminated between an amplitude of a track previous to theprevious track of the second disk surface and an amplitude of theinitial track of the second disk surface.

[0017] In additional implementations, the first disk surface and thesecond disk surface are members of a plurality of disk surfaces, whereinthe plurality of tracks are arranged concentrically on each disk surfacewith each track having an index, wherein the index ranges from onethrough a total number of the plurality of tracks on each disk surface,wherein the number of tracks on each disk surface is identical, andwherein the track having the index of one is located nearest to thecenter of a disk surface adjacent to a crash stop. In oneimplementation, the index of the initial track, the previous track, andnext track are repetitively incremented by one and following eachincrementing, the compound actuator is moved, the first head ispositioned, the next track of the second disk surface written, thesecond head positioned, and the next track on the first disk surfacewritten, until all tracks are servowritten.

[0018] In another implementation, the self-servowriting system comprisesadditional heads wherein any of the additional heads may be used fortrack following, wherein the track following comprises positioning onehead of the additional heads, and based on the track following writingservo tracks with heads other than the one head.

[0019] The implementations allow a track following head to track followbetween two already written tracks by noise elimination between the twoalready written tracks. As a result, the accuracy of writing the servotracks is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Referring now to the drawings in which like reference numbersrepresent corresponding parts throughout:

[0021]FIG. 1 illustrates a block diagram of prior art servo burstpatterns written on a disk surface;

[0022]FIG. 2 illustrates a block diagram of prior art servo burstpatterns written on multiple disk surfaces by a single stage actuator;

[0023]FIG. 3 illustrates a block diagram of a prior art noisecancellation technique for self-servowriting;

[0024]FIG. 4 illustrates a block diagram of a compound actuator inaccordance with certain described implementations of the invention;

[0025]FIGS. 5a and 5 b illustrate servo burst patterns in accordancewith certain described implementations of the invention;

[0026]FIGS. 6a and 6 b illustrate data tracks and servo tracks inaccordance with certain described implementations of the invention;

[0027]FIG. 7 illustrates the operation of a compound actuator inaccordance with certain described implementations of the invention;

[0028]FIG. 8 illustrates logic implemented in a compound actuator forself-servowriting in accordance with certain described implementationsof the invention; and

[0029]FIGS. 9 and 10 illustrates blocks diagrams indicating thepositions of the heads during self-servowriting in accordance withcertain described implementations of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] In the following description, reference is made to theaccompanying drawings which form a part hereof and which illustrateseveral implementations. It is understood that other implementations maybe utilized and structural and operational changes may be made withoutdeparting from the scope of the present implementations.

[0031]FIG. 4 illustrates a schematic diagram of a hard disk 80containing a compound actuator 81. Unlike single stage actuators whereall heads move to the same track with the actuator, a compound actuatorenables each of the heads to move by a few tracks independently of theposition of the actuator. For example, if a compound actuator is onservo track 100, a first head may move to servo track 99, a second headto servo track 101, and a third head may stay on servo track 100. Arotary actuator with a milli actuator on the head suspension is anexample of a compound actuator. A compound actuator can of course moveacross the entire disk surface, potentially moving across thousands oftracks in one movement. Compound actuators can position the heads moreprecisely than a single stage actuator because of the independent headmovements.

[0032] The compound actuator 81 has a plurality of heads 82 a . . . 82f. A controller 83 controls the movement of the compound actuator 81 andthe plurality of heads 82 a . . . 82 f. The controller 83 may comprisehardware or software and may be part of or be external to the hard disk80. The hard disk 80 has a plurality of disk surfaces 84 a . . . 84 f.Each head 82 a . . . 82 f reads and writes to a disk surface 84 a . . .84 f, respectively. Although, only six heads and six disk surfaces areshown in FIG. 4, the hard disk 80 may have a different number of disksurfaces and heads, for example there may be seven heads and seven disksurfaces. The compound actuator 81 moves (reference numeral 86 exhibitsthe actuator movement) radially across the disk surfaces 84 a . . . 84 fand may rigidly move the heads 82 a . . . 82 f on the disk surfaces 84 a. . . 84 f, respectively. Independent of the actuator movement 86, eachof the heads 82 a . . . 82 f can move (reference numeral 88 exhibits anexemplary independent head movement) a few tracks radially across thedisk surface. The hard disk 80 has a crash stop 89 at the innermostdiameter of each of the disk surfaces 84 a . . . 84 f. In someimplementations, there maybe a crash stop at the outermost diameter ofthe disk surfaces 84 a . . . 84 f. In some implementations, the heads 82a . . . 82 f can write servo tracks on the disk surfaces 84 a . . . 84 fstarting from the precisely known position of the innermost crash stop89. Other implementations may use the crash stop at the outermostdiameter of the disk surfaces 84 a . . . 84 f.

[0033] However, even in compound actuators, the same voltage whenapplied to two heads may cause slightly different movements on the twoheads. In contrast, if one head called the track following head isprecisely positioned and the other heads moved relative to the trackfollowing head, then the other heads can self-servo write moreprecisely.

[0034]FIG. 5a illustrates a schematic diagram, in accordance withimplementations of the invention, of four servo burst patterns A, B, Cand D (reference numerals 90 a, 90 b, 90 c, and 90 d respectively)written across the servo tracks 92 of the disk 80, having the compoundactuator 81, disk heads 82 a . . . 82 f, and disk surfaces 84 a . . . 84f Each servo burst pattern 90 a, 90 b, 90 c, and 90 d is half a datatrack in width.

[0035]FIG. 5b illustrates a schematic diagram, in accordance withimplementations of the invention, of the four servo burst patterns 90 a. . . 90 d as written with respect to the entire disk surface 84 a . . .84 f and the servo tracks 92 in a top view. Each servo track shown inthe servo tracks 92 has an index, where the index ranges from onethrough the total number of servo tracks on each disk surface, where thenumber of tracks on each disk surface is identical. In this case, thetrack having the index of one is located nearest to the center of a disksurface adjacent to the crash stop 89.

[0036]FIG. 6a shows a collection of data tracks 102 on the disk surface84 a . . . 84 f. Applications can write data onto the data tracks 102.The data tracks 102 are concentric around the center of the disk surface84 a . . . 84 f.

[0037]FIG. 6b shows a collection of servo tracks 104 on the disk surface84 a . . . 84 f. The compound actuator 81 writes servo bursts 90 a . . .90 d on the servo tracks 104 before any data is written on the datatracks 102. Each servo burst pattern 90 a . . . 90 d is the width of adata track 102. However because adjacent servo burst patterns 90 a, 90b, 90 c, and 90 d overlap each other by half the width of a servo (ordata) track, there are twice as many servo tracks 104 on a disk surface84 a . . . 84 f as there are data tracks 102.

[0038]FIG. 7 shows compound actuator 81 with head 82 a on disk surface84 a, head 82 b on disk surface 84 b, and head 82 c on disk surface 84c. Only four servo tracks 108, 109, 110, and 111 are shown on each disksurface 84 a, 84 b, and 84 c. The number of servo tracks can vary from 1to the highest track number on the disk surfaces 84 a, 84 b, 84 c. Servotrack 110 corresponds to servo track n, and servo tracks 111, 109, 108correspond to servo tracks n+1, n−1, n−2 respectively. The number n canvary from 1 to the highest number of servo tracks.

[0039] In FIG. 7, the position of the compound actuator 81 and heads 82a-82 c are shown in accordance with one embodiment of the presentinvention. In this configuration, the compound actuator 81 is positionedon servo track n 110. Head 82 a is on the same servo track n 110 as thecompound actuator 81. However, head 82 b is one servo track behind onservo track n−1 109, and head 82 c is one servo track ahead on servotrack n+1 111. Each head 82 a, 82 b, 82 c can move at least one servotrack ahead and at least one servo track behind the actuator servo trackposition in a manner known in the art. Thus, the heads 82 a, 82 b, and82 c can move independently on the compound actuator.

[0040]FIG. 8 illustrates logic implemented in a controller of aself-servo writing system for writing self-servo bursts on the disksurfaces 84 a, . . . c in accordance with the present invention. Whilethe implementation has three disk surfaces, the logic applies to thehard disk 80 with two or more disk surfaces. In one implementation, theself-servowriting system begins the self-servowriting process by movingthe compound actuator 81 along with all three heads 82 a, 82 b, and 82 cto rest against the crash stop 89 (since the heads are resting againstthe crash stop 89 the heads are positioned for writing very precisely)at the center of the hard disk 80, and each head 82 a, 82 b, 82 c servowrites servo burst B 90 b on servo track 2. The self-servowriting systemassigns track 2 to n. Heads 82 a, 82 b, 82 c then move to servo track 1,i.e n−1, and heads 82 a, 82 b, 82 c write servo burst A 90 a. Heads 82a, 82 b, 82 c then move to servo track 3, i.e n+1, and heads 82 a, 82 b,82 c, 82 d write servo burst C 90 c.

[0041] In alternative implementations, the heads 82 a, 82 b, 82 c mayexhibit independent movements of more than one track on either side ofthe position of the compound actuator 81. For example, the heads 82 a,82 b, 82 c may move up to two tracks ahead of the position of thecompound actuator 81 and two tracks behind the position of the compoundactuator 81. In some implementations the self-servowriting system mayassign a track other than track 2 to n. For example, theself-servowriting system may assign track 3 to n, and the heads 82 a, 82b, 82 c may then move to any of the tracks from 1 to 5.

[0042] At block 120, the compound actuator 81 moves to servo track n+1.Servo tracks n−1, n, and n+1 have already been written. The heads 82 a,82 b, 82 c move (at block 121) with the compound actuator 81 to servotrack n+1. At block 122, head 82 a moves and positions precisely onservo track n. Track following is achieved using the servo burstswritten on servo tracks n−1, n, and n+1. For precise positioning of head82 a on servo track n, white noise is eliminated by subtracting theburst information written on tracks n−1 and n+1 as described in FIG. 3.

[0043] With head 82 a positioning precisely and track following (atblock 122) on servo track n, heads 82 b, 82 c move (at block 124) toservo track n+2 and servo write (at block 125) track n+2. Head 82 b thenmoves (at block 128) independently to servo track n and positionsprecisely and track follows on track n. For precise positioning of head82 b on servo track n, white noise is eliminated by subtracting theburst information written on tracks n−1 and n+1 as described in FIG. 3.Head 82 a then moves (at block 130) to track n+2 and servo writes (atblock 131) track n+2.

[0044] At the conclusion of block 131, control proceeds to block 132where n is incremented by one and the blocks 120 to 131 are repeatedover and over until all servo tracks on all disk surfaces 84 a, 84 b, 84c are written with servo burst patterns 90 a . . . 90 d from servo track1 to the highest number of servo tracks.

[0045] In FIG. 9, the compound actuator 81 and head positions 142 a, 142b, and 142 c are shown at time t 150 corresponding to block 124 in FIG.8. In FIG. 9 head 82 a is one track behind the position of the compoundactuator 81 and heads 82 b and 82 c are one track ahead of the compoundactuator 81. Head 82 a is track following precisely on track n usingpreviously written servo track burst information 90 a, 90 b, 90 c, and90 d to keep on track and cancel out white noise as described in FIG. 3.

[0046]FIG. 10 shows the compound actuator 81 and head positions 146 a,146 b, and 146 c at time t+1 152, where t+1 152 is a time that issubsequent to time t 150. FIG. 10 corresponds to block 130 in FIG. 8. InFIG. 10, head 82 b is one track behind the position of the compoundactuator 81 and head 82 a and 82 c are one track ahead of the compoundactuator 81. Head 82 b now takes over the track following task on trackn allowing head 82 a to write servo track n+2.

[0047] In an alternative implementation of the logic shown in FIG. 8, atblock 128, instead of using head 82 b moving to servo track n, head 82 ccould be moved to servo track n and in block 128 head 82 c could havebeen the track follow head instead of head 82 b.

[0048] While the implementation described in FIG. 8 has been shown withthree heads, the logic could be applied with only two heads. In such acase, a first head would be the track following head and the second headwould write servo tracks. Subsequently, the second head would be thetrack following head, and the first head would write servo tracks.

[0049] With the compound actuator 81, there is no need for trackfollowing on single burst half track (track following on single bursthalf track was shown on the first surface 50 a of FIG. 2) as was thecase in prior art. The heads of the compound actuator 81 writeself-servo patterns more precisely when compared to the situation wherethe heads cannot move independently of an actuator. The describedimplementations improve accuracy because earlier written servo burstsare used for noise elimination while positioning a track following head,and based on the positioning of the track following head the other headswrite servo tracks.

[0050] The implementations allow the track following head to trackfollow between two already written servo tracks. The result is a muchmore precise series of servo tracks because the self-servo write processcan compensate for any deviation from servo track center. Higher servowrite rotational speeds can also be used for servo-writing. Furthermore,compound actuator based self-servo writes do not require an expensivepusher-based servowriting equipment.

Additional Implementation Details

[0051] The described self-servo writing techniques may be implemented asa method, apparatus or article of manufacture using standard programmingand/or engineering techniques to produce software, firmware, hardware,or any combination thereof. The term “article of manufacture” as usedherein refers to code or logic implemented in hardware logic (e.g., anintegrated circuit chip, Field Programmable Gate Array (FPGA),Application Specific Integrated Circuit (ASIC), etc.) or a computerreadable medium (e.g., magnetic storage medium (e.g., hard disk drives,floppy disks,, tape, etc.), optical storage (CD-ROMs, optical disks,etc.), volatile and non-volatile memory devices (e.g., EEPROMs, ROMs,PROMs, RAMs, DRAMs, SRAMs, firmware, programmable logic, etc.). Code inthe computer readable medium is accessed and executed by a processor.The code in which implementations are made may further be accessiblethrough a transmission media or from a file server over a network. Insuch cases, the article of manufacture in which the code is implementedmay comprise a transmission media, such as a network transmission line,wireless transmission media, signals propagating through space, radiowaves, infrared signals, etc. Of course, those skilled in the art willrecognize that many modifications may be made to this configurationwithout departing from the scope of the implementations, and that thearticle of manufacture may comprise any information bearing medium knownin the art.

[0052] The logic of FIG. 8 described specific operations occurring in aparticular order. Further, the steps may be performed in parallel aswell as sequentially. In alternative embodiments, certain of the logicoperations may be performed in a different order, modified or removedand still implement preferred embodiments of the present invention.Morever, steps may be added to the above described logic and stillconform to the preferred embodiments.

[0053] There are several ways of arranging servo information. In the“wedge servo” implementation, the servo information is recorded in awedge of each platter-shaped disk. In “embedded servo,” servoinformation is interspersed with data across the entire surface of allthe hard disk platter surfaces. The implementations described can beadapted for either “wedge servo” or “embedded servo” methods ofarranging servo information, or any other arrangement of servo dataknown in the art.

[0054] In the described implementations, the servo track width is thesame as the data track width, and adjacent servo tracks are offset byhalf a track width. Variations of the implementation where the servotrack width is different from the data track width, and where the offsetbetween adjacent servo tracks is different from half a track width arepossible. For example, implementations where adjacent servo tracksoverlap each other by a third of a track width, or do not overlap at allare possible.

[0055] In the described implementations, each head moves one servo trackahead and one servo track behind an actuator track position. Alternativeimplementations where the heads move a different number of servo tracksahead and behind the actuator track position are possible.

[0056] Therefore, the foregoing description of the implementations hasbeen presented for the purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform disclosed. Many modifications and variations are possible in lightof the above teaching. It is intended that the scope of the invention belimited not by this detailed description, but rather by the claimsappended hereto. The above specification, examples and data provide acomplete description of the manufacture and use of the composition ofthe invention. Since many embodiments of the invention can be madewithout departing from the spirit and scope of the invention, theinvention resides in the claims hereinafter appended.

What is claimed is:
 1. A method for servo writing, the methodcomprising: positioning a first head on a first track of a first disksurface; using the positioning of the first head on the first disksurface to position a second head on a second track on a second disksurface; writing, servo information with the second head at the positionof the second track on the second disk surface; positioning the secondhead on a first track of the second disk surface; using the positioningof the second head on the second disk surface to position the first headon a second track of the first disk surface; and writing servoinformation with the first head at the position of the second track ofthe first disk surface, wherein the first and second tracks are anytracks on the first and second disk surfaces.
 2. The method of claim 1,further comprising: reading servo information from at least two tracks,wherein the read servo information is used to position the second headon the first track of the second disk surface in a manner thateliminates white noise.
 3. The method of claim 2, wherein the servoinformation is read from one of two tracks on a same disk surface or twotracks from different disk surfaces.
 4. The method of claim 2, whereinthe white noise is eliminated between amplitudes of the at least twotracks from which the servo information was read.
 5. The method of claim1, wherein additional heads are used, and wherein one head of theadditional heads is positioned, and based on the positioning of the onehead writing servo tracks with heads other than the one head.
 6. Amethod for writing a plurality of tracks in a self-servowriting system,the method comprising: moving a compound actuator having a first and asecond head to an initial track; positioning the first head on aprevious track with respect to the initial track on a first disksurface; servowriting a next track with respect to the initial track ona second disk surface with the second head; positioning the second headon the previous track of the second disk surface; and servowriting thenext track on the first disk surface with the first head.
 7. The methodof claim 6, wherein positioning the second head on the previous track ofthe second disk surface further comprises: moving the second head to aposition on the second disk surface wherein a white noise is eliminatedbetween an amplitude of a track previous to the previous track of thesecond disk surface and an amplitude of the initial track of the seconddisk surface.
 8. The method of claim 6, wherein writing the next trackof the second disk surface by the second head, further comprises:determining a first position of the compound actuator; determining asecond position of the first head; positioning the second head relativeto the first position and the second position to the next track; andwriting the next track on the second disk surface.
 9. The method ofclaim 6, wherein writing the next track on the first disk surface withthe first head, further comprises: determining a first position of thecompound actuator; determining a second position of the second head;positioning the first head relative to the first position and the secondposition to the next track; and writing the next track on the first disksurface.
 10. The method of claim 6, wherein each track is a servo trackhaving a servo track width, wherein the servo track width is same as thewidth of a data track.
 11. The method of claim 6, wherein each track iscapable of having servo burst patterns written on the track, and whereinthe number of servo burst patterns is four.
 12. The method of claim 6,wherein each track is a servo track, and both the first disk surface andsecond disk surface have twice as many servo tracks as data tracks. 13.The method of claim 6, wherein the first disk surface and the seconddisk surface are members of a plurality of disk surfaces, wherein theplurality of tracks are arranged concentrically on each disk surfacewith each track having an index, wherein the index ranges from onethrough a total number of the plurality of tracks on each disk surface,wherein the number of tracks on each disk surface is identical, andwherein the track having the index of one is located nearest to thecenter of a disk surface adjacent to a crash stop.
 14. The method ofclaim 13, further comprising, repetitively: (i) incrementing the indexof the initial track, the previous track, and next track by one; and(ii) following each incrementing, moving the compound actuator;positioning the first head, writing the next track of the second disksurface; and positioning the second head, and writing the next track onthe first disk surface; until all tracks are servowritten.
 15. Themethod of claim 6, wherein the compound actuator has a third head,further comprising: subsequent to positioning the first head on theprevious track of the first disk surface; writing a next track of athird disk surface with the third head; and subsequent to writing thenext track of the third disk surface with the third head and prior towriting the next track on the first disk surface with the first head,positioning the third head on a previous track of the third disksurface.
 16. The method of claim 6, wherein the self-servowriting systemcomprises additional heads wherein any of the additional heads may beused for track following, wherein the track following comprisespositioning one head of the additional heads, and based on the trackfollowing writing servo tracks with heads other than the one head.
 17. Asystem for servo writing, the system comprising: a first disk surface; asecond disk surface; a first head; a second head; means for positioningthe first head on a first track of the first disk surface; means forusing the positioning of the first head on the first disk surface toposition the second head on a second track on the second disk surface;means for writing servo information with the second head at the positionof the second track on the second disk surface; means for positioningthe second head on a first track of the second disk surface; means forusing the positioning of the second head on the second disk surface toposition the first head on a second track of the first disk surface; andmeans for writing servo information with the first head at the positionof the second track of the first disk surface, wherein the first andsecond tracks are any tracks on the first and second disk surfaces. 18.The system of claim 17, further comprising: means for reading servoinformation from at least two tracks, wherein the read servo informationis used to position the second on the first track of the second disksurface in a manner that eliminates white noise.
 19. The system of claim18, wherein the servo information is read from one of two tracks on asame disk surface or two tracks from different disk surfaces.
 20. Thesystem of claim 18, wherein the white noise is eliminates betweenamplitudes of the at least two tracks from which the servo informationwas read.
 21. The system of claim 16, wherein the actuator hasadditional heads, and wherein one head of the additional heads ispositioned, the system further comprising: means for writing servotracks with heads other than the one head based on the positioning ofthe one head
 22. A system for writing a plurality of tracks in aself-servowriting system, the system comprising: an actuator having afirst head and a second head; means for moving the actuator to aninitial track; means for positioning the first head on a previous trackof a first disk surface; means for writing a next track of a second disksurface with the second head; means for positioning the second head onthe previous track of the second disk surface; and means for writing thenext track on the first disk surface with the first head.
 23. The systemof claim 22, wherein the means for positioning the second head on theprevious track of the second disk surface further performs: moving thesecond head to a position on the second disk surface wherein a whitenoise is eliminated between an amplitude of a track previous to theprevious track of the second disk surface and an amplitude of theinitial track of the second disk surface.
 24. The system of claim 22,wherein the means for writing the next track of the second disk surfaceby the second head, further performs: determining a first position ofthe actuator; determining a second position of the first head;positioning the second head relative to the first position and thesecond position to the next track; and writing the next track on thesecond disk surface.
 25. The system of claim 22, wherein the means forwriting the next track on the first disk surface with the first head,further performs: determining a first position of the actuator;determining a second position of the second head; positioning the firsthead relative to the first position and the second position to the nexttrack; and writing the next track on the first disk surface.
 26. Thesystem of claim 22, wherein each track is a servo track having a servotrack width, wherein the servo track width is same as the width of adata track.
 27. The system of claim 22, wherein each track is capable ofhaving servo burst patterns written on the track, and wherein the numberof servo burst patterns is four.
 28. The system of claim 22, whereineach track is a servo track, and both the first disk surface and seconddisk surface have twice as many servo tracks as data tracks.
 29. Thesystem of claim 22, wherein the first disk surface and the second disksurface are members of a plurality of disk surfaces, wherein theplurality of tracks are arranged concentrically on each disk surfacewith each track having an index, wherein the index ranges from onethrough a total number of the plurality of tracks on each disk surface,wherein the number of tracks on each disk surface is identical, andwherein the track having the index of one is located nearest to thecenter of a disk surface adjacent to a crash stop.
 30. The system ofclaim 27, further comprising means for repetitively performing: (i)incrementing the index of the initial track, the previous track, andnext track by one; and (ii) following each incrementing, moving theactuator, positioning the first head, writing the next track of thesecond disk surface, positioning the second head, and writing the nexttrack on the first disk surface; until all tracks are servowritten. 31.The system of claim 22, wherein the actuator has a third head, furthercomprising: means for writing a next track of a third disk surface withthe third head, subsequent to positioning the first head on the previoustrack of the first disk surface; and means for positioning the thirdhead on a previous track of the third disk surface, subsequent towriting the next track of the third disk surface with the third head andprior to writing the next track on the first disk surface with the firsthead.
 32. The system of claim 22, wherein the self-servowriting systemcomprises additional heads wherein any of the additional heads may beused for track following, wherein the track following comprisespositioning one head of the additional heads, and based on the trackfollowing writing servo tracks with heads other than the one head. 33.An article of manufacturing for servo writing, wherein the article ofmanufacturing is capable of causing operations, the operationscomprising: positioning a first head on a first track of a first disksurface; using the positioning of the first head on the first disksurface to position a second head on a second track on a second disksurface; writing servo information with the second head at the positionof the second track on the second disk surface; positioning the secondhead on a first track of the second disk surface; using the positioningof the second head on the second disk surface to position the first headon a second track of the first disk surface; and writing servoinformation with the first head at the position of the second track ofthe first disk surface, wherein the first and second tracks are anytracks on the first and second disk surfaces.
 34. The article ofmanufacture of 33, further comprising: reading servo information from atleast two tracks, wherein the read servo information is used to positionthe second on the first track of the second disk surface in a mannerthat eliminates white noise.
 35. The article of manufacture of 34,wherein the servo information is read from one of two tracks on a samedisk surface or two tracks from different disk surfaces.
 36. The articleof manufacture of 34, wherein the white noise is eliminates betweenamplitudes of the at least two tracks from which the servo informationwas read.
 37. The article of manufacture of claim 33, wherein additionalheads are used, and wherein one head of the additional heads ispositioned, and based on the positioning of the one head writing servotracks with heads other than the one head.
 38. An article of manufacturefor writing a plurality of tracks in a self-servowriting system, whereinthe article of manufacture causes operations, the operations comprising:moving a compound actuator having a first and a second head to aninitial track; positioning the first head on a previous track of a firstdisk surface; writing a next track of a second disk surface with thesecond head; positioning the second head on the previous track of thesecond disk surface; and writing the next track on the first disksurface with the first head.
 39. The article of manufacture of claim 38,wherein positioning the second head on the previous track of the seconddisk surface further comprises: moving the second head to a position onthe second disk surface wherein a white noise is eliminated between anamplitude of a track previous to the previous track of the second disksurface and an amplitude of the initial track of the second disksurface.
 40. The article of manufacture of claim 38, wherein writing thenext track of the second disk surface by the second head, furthercomprises: determining a first position of the compound actuator;determining a second position of the first head; positioning the secondhead relative to the first position and the second position to the nexttrack; and writing the next track on the second disk surface.
 41. Thearticle of manufacture of claim 38, wherein writing the next track onthe first disk surface with the first head, further comprises:determining a first position of the compound actuator; determining asecond position of the second head; positioning the first head relativeto the first position and the second position to the next track; andwriting the next track on the first disk surface.
 41. The article ofmanufacture of claim 38, wherein each track is a servo track having aservo track width, wherein the servo track width is same as the width ofa data track.
 42. The article of manufacture of claim 38, wherein eachtrack is capable of having servo burst patterns written on the track,and wherein the number of servo burst patterns is four.
 43. The articleof manufacture of claim 38, wherein each track is a servo track, andboth the first disk surface and second disk surface have twice as manyservo tracks as data tracks.
 44. The article of manufacture of claim 38,wherein the first disk surface and the second disk surface are membersof a plurality of disk surfaces, wherein the plurality of tracks arearranged concentrically on each disk surface with each track having anindex, wherein the index ranges from one through a total number of theplurality of tracks on each disk surface, wherein the number of trackson each disk surface is identical, and wherein the track having theindex of one is located nearest to the center of a disk surface adjacentto a crash stop.
 45. The article of manufacture of claim 44, theoperations further comprising, repetitively: (i) incrementing the indexof the initial track, the previous track, and next track by one; and(ii) following each incrementing, moving the compound actuator,positioning the first head, writing the next track of the second disksurface, positioning the second head, and writing the next track on thefirst disk surface; until all tracks are servowritten.
 46. The articleof manufacture of claim 38, wherein the compound actuator has a thirdhead, the operations further comprising: subsequent to positioning thefirst head on the previous track of the first disk surface, writing anext track of a third disk surface with the third head; subsequent towriting the next track of the third disk surface with the third head andprior to writing the next track on the first disk surface with the firsthead, positioning the third head on a previous track of the third disksurface.
 47. The article of manufacture of claim 38, wherein theself-servowriting system comprises additional heads wherein any of theadditional heads may be used for track following, wherein the trackfollowing comprises positioning one head of the additional heads, andbased on the track following writing servo tracks with heads other thanthe one head.